standard practice with old TTL 'jelly bean' logic I.C.'s was one bypass c= ap. (0.1uF) in parallel with the power supply smoothing cap. (100uF),AND a 10= 0nF between each supply as close as possible to EACH I.C. to filter out mains hum and short spikes on the supply rails.This 'rule of thumb' still holds true. ----- Original Message ----- From: "Mauricio Giovagnini" To: "Microcontroller discussion list - Public." Sent: Friday, November 18, 2005 1:40 PM Subject: Re: [PIC] : 16F877 vs 16F877A Can you reproduce the exact problem? when it happens? I read on the Microchip forum, many months ago that the 77 series are m= ore inmune to noise. If its electrical, then check putting some capacitors here and there. An inductor in series should work also. If your problem is related to magnetic interference, not electrical, th= en consider using a faraday shielding. Rodrigo Real escribi=F3: Mauricio Giovagnini writes: Hi guys I had a problem with these new version, with the 'A'. I work with a motor controller, and when I swithced from 16F877 to 16F877= A I had electric interference which made the PIC resets and get crazy sometimes. I could solve these isolating a bit more the logic part and the power side of my circuit, but it was a little hard. And in fact I am not sure if I won't have problems with that in a near future. Rodrigo > The PIC16F877A has a comparator, and the 77 doesn't > > > I also remember having read on the Microchip forum and some websites that the A have a better algorythm for 'code protection'. > > They also have an enhanced eeprom and flash, that will give you more writing cycles. > > > > > alan smith escribi=F3:Did some searching.....and havent found a real = good description of the 877A updates. From what I know, it has changes in the programming algorithims, and it fixes a problem with the PORTB read/modify/write but what else? > > > --------------------------------- > Yahoo! FareChase - Search multiple travel sites in one click. > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > --------------------------------- > 1GB gratis, Antivirus y Antispam > Correo Yahoo!, el mejor correo web del mundo > Abr=ED tu cuenta aqu=ED > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --------------------------------- 1GB gratis, Antivirus y Antispam Correo Yahoo!, el mejor correo web del mundo Abr=ED tu cuenta aqu=ED -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist